Imagine, for example, that you have been placed in a room and asked to watch a series of student speeches on the policies of Venezuelan leader Hugo Chávez. You've been told in advance that the students were assigned the task of either attacking or supporting Chávez and had no choice in the matter. Now, suppose that you are then asked to assess the political leanings of these students. Shrewd observers, of course, would factor in the context and adjust their assessments accordingly. A student who gave an enthusiastic pro-Chávez speech was merely doing what she was told, not revealing anything about her true attitudes. In fact, many experiments suggest that people would overwhelmingly rate the pro-Chávez speakers as more leftist. Even when alerted to context that should affect their judgment, people tend to ignore it. Instead, they attribute the behavior they see to the person's nature, character, or persistent motives. This bias is so robust and common that social psychologists have given it a lofty title: They call it the fundamental attribution error.
Link here through FP.